A flexible ServerNet-based fault-tolerant architecture

The paper introduces a new fault-tolerant architecture that combines the best attributes of the software fault-tolerant Tandem NonStop systems with the hardware fault-tolerant integrity systems. This architecture is based on the ServerNet System Area Network (SAN). ServerNet, formerly called TNet, is a packetized byte-serial multistage network that supports both I/O and interprocessor traffic in fault-tolerant systems. Dual-ported CPUs and VO controllers connect to independent subnetworks in a variety of different network topologies. Systems can expand either through shared or distributed memory multiprocessing. A separate maintenance system controls system initialization, online configuration changes, and error reporting. The architecture´s flexibility makes it suitable for a wide range of environments with varying requirements for performance, fault tolerance, and software compatibility.<>